A giant explosion occurs during the loading of fertilizer onto the freighter Grandcamp at a pier in Texas City, Texas, on this day in 1947. Nearly 600 people lost their lives and thousands were injured when the ship was literally blown to bits.

Ammonium nitrate was used as an explosive by the U.S. Army in World War II and, after the war ended, production of the chemical continued as its use as a fertilizer became accepted. However, the precautions used in its transport became far more lax in the post-war years.

On April 16, the Grandcamp was being loaded with ammonium nitrate as well as tobacco and government-owned ammunition. Cigarette smoking, although officially banned, was a common practice by longshoremen on the docks. Just two days prior to the explosion, a cigarette had caused a fire on the docks. On the morning of April 16, smoke was spotted deep within one of the Grandcamp‘s holds.

Some water and an extinguisher were used to fight the fire, but hoses were not employed for fear of ruining the cargo; there were already 2,300 tons loaded on the ship. While the ammunition was removed from the ship, the crew attempted to restrict oxygen to the hold in hopes of putting out the fire. Apparently they did not realize that because of ammonium nitrate’s chemical composition, it does not require oxygen in order to burn.

By 9 a.m., flames had erupted from the hold and within minutes it exploded. The blast was heard 150 miles away and was so powerful that the ship’s 1.5- ton anchor was found two miles away. The force of the explosion lifted another ship right out of the water. People working at the docks were killed instantly.

Pieces of flaming debris damaged the oil refineries in the area. A nearby Monsanto chemical storage facility also exploded, killing 234 of the 574 workers there. Nearly all of the survivors were seriously injured. A residential area of 500 homes was also leveled by the blast. Another ship, the High Flyer, which was carrying similar cargo, was pushed completely across the harbor. The crew fled when it came to rest, failing to notice that a fire had started and the next day their ship also exploded. Two people died.

In all, 581 people died and 3,500 were injured. The explosion caused $100 million in damages. A long-disputed court case over the cause of the blast was resolved when Congress granted compensation to 1,394 victims. They received a total of $17 million in 1955. The port was rebuilt to handle oil products only.